Fluted perforating punch devices or tools



Aug. 12, 1958 J. F. KOPCZYNS'KI 2,347,069

FLUTED PERFORATING PUNCH DEVICES OR TOOLS Filed D90. 6, 1955 2 Sheets-Sheet 1 IN VEN TOR.

'75} L257? 170 Gig/77551 6 B v WWW Aug. 12, 1958 J. F. KOPCZYNSKI 2,847,069

FLUTED PERFORATING PUNCH DEVICES OR TOOLS Filed Dec. 6; 1955 2 Sheets-Sheet 2 %77 73 I 9 77 25 A i 6 A V I INVENTOR.

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United States Patent FLUTED PERFORATING PUNCH DEVICES OR TOOLS John F. Kopczynski, North Touawanda, N. Y.

Application December 6, 1955, Serial No. 551,376

7 Claims. (Cl. 164-'124) This invention relates to punch devicesor tools for perforating sheet material, and especially to thepiercing punchitself.

An object of the invention is to provide an, improved punch device for perforating sheet material, with which the piercing element will effectively pierce the sheet material and in its reciprocations may be guided by the stripper plate with which the piercing element may operate for unusually long periods of use without breakage, and which requires little modification of existing machines for perforating sheet material.

Another object of the invention is to provide a piercing element for perforating punch devices which will be exceptionally durable and practicalin use, of relatively long operating life, have maximum strength in'resisting breakagevduring a punching operation, which may be maderof one integral piece of metal and directly from a hardened blank without causing the blank to lose its hardness, which. will produce clean apertures, and which will be relatively simple, effective and inexpensive:

A further object is to provide an improved, practical, simple and relatively inexpensive method of forming piercing elements or punches for perforating sheet material from an integral blank of metal, and with which theelements will have maximum resistance to breakage m use and an integral guide and reinforcement at thev portions where breakage is most likely to occur in use.

Other objects and advantages will be apparent from the following description of one embodiment of: the invention and one application of the method, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawings:

Fig. l is a sectional elevationofa punch device made inaccordance with this invention and illustrating in elevation the perforating element of this invention at the start of a perforation;

Fig. 2 is a perspective of the new perforating element;

Fig. 3 is an end elevation of the same;

Fig. 4 is a longitudinal, sectional elevation of the same;

Figs. 5, 6 and 7 are horizontal, sectional plans of the same, the sections being taken on lines 5-5, 6-6 and 7-7 respectively;

Fig. 8 is a side elevation of a grinding wheel that may be employed in the method of forming the perforating element;

Fig. 9 is a sectional elevation, lengthwise of the perforating element, and illustrating the manner in which the first flute is ground on a hardened punch blank;

Fig. 10 is a vertical, transverse, sectional elevation of the' same, the section being taken approximately along 'theline 10-10 of Fig. 9; and

Fig. 11 is a sectional elevation similar to Fig. 1, but illustrating a modification thereof, without a guide sleeve. In the embodiment of the invention illustrated in Figs. 1 to 10, the punch device includes anapertured die 1 supported in a recess 2 in a base 3, the base having a passage 4 alined withand larger than the-.aperturef5 5 has a liner sleeve 7 therein alined with the ,die 1, with of the shank 12 and spaced apart.

thepassage 8 of the sleeve larger than theaperture 5 0f the die 1.

A perforatingelement orpunch 9, shown separately inFig. 2, has a head 10 which, is detachably mounted ina holder 11 in the usual manner. The element;:9 is formed of a body of hardened-metal, such ashardened steel, and has .a cylindrical shank 12 whichv is slidingly guided in the passage 8 of thelinensleeve 7, asshown in Fig. l. The free or perforating-endv or. stem 13 of the element 9 has a cross sectional area substantiallydess than the cross sectional area of the, shank .12., The peripheralsurface of thestemlS-continues 'endwise into the adjacent end of the shankg12 as flutes or, channels 14 that are, arranged at intervals around-the periphery These flutes, 14, after they enter the end of the shank 12, become progressively shallower, with the bottom of each:flute in theform of an arc 15 (see Fig. 4) in a plane, lengthwise of the shank, and also an arc of a circle 16; in. transverse cross. section, with the center of curvature of 'the arcof a circle 16-in the longitudinal axis ofthe shank, as, shown in Figs.- ,4, 6 and 7.

The flutes 14 intersect with adjacentflutes as they enter the, end of the shank 12, as shownin Fig. 5,;but-become separated by the, shankas th y: Progress fartherinto the shank end, as shown by the, sections of Figs.- 5, 6 and 7. This provides a plurality of tonguesorfingers -17 extending; endwise from the shanlelZ along the stem and; spaced from the stern attheir free ends. The outer-walls 18. of

the fingers 17 are continuations of. the cylindricahperiph- The-preferred method offorming this perforating ele- I ment or punch 9 is to form the body with the shankand head of the desired size and shape, with an end of reduced diameter for the stem 13. Thestemrl3 is preferably left slightly larger in diameter than is desired for the, finalstem,-.and this stern may be machined-in any desired manner to this slightly larger diameter. The punchbody is then, mounted. or chuckedfor rotation, so that the stemend is free and may be rotated about its. longitudinal axis throughjselected increments of rota tion, such vas threein this example. Whilethe punch body, is soheld inone of its angular positions, a grind: ing wheel 19 is moved, along and in; contact with the stem 13 from the free end of the stem toits other end attached to .theshank, and intothe, shank to theextent shown by dash lines inFig 9. This grinding whe,el 19 is mounted in fixed relation on a rotatable.shaft 20, Fig.8, so as-to rotate-therewith, and this shaft is disposed crosswise of the axis of the stem- 13, as shown in Fig. 9 andmoved in the direction of the arrow A in Fig. 9 until the rotating grinding wheel 19 reaches the position shown in dash lines in Fig. 9.

The peripheral grindingsurface of the wheel .19, in transverse cross section, has the shape of an are D of a circle (Figs. 8 and 10) whose radius is equal to the radius of the desired radius of the cylindrical surface of the stern. As the wheel 19 moves against the end. of

the shank 12, it grinds a flute 14 therein, as shown in Figs. 9 and 10, and at the same time grinds an arc of the desired peripheral surface C of the stem (see Fig. 10). After this operation, the wheel 19 is moved from the stem and the perforating element rotated angularly about its longitudinal axis into a position for another flute to be formed. Then another similar grinding operation is performed on the element which grinds a new are C on the stem that meets edgewise with the previously formed are C on the stem, and also forms another flute that intersects with the previously formed flute at the start of the flute, but becomes separated therefrom as the grinding of the flute farther into the shank continues. After this second flute is formed, the element is again rotated into another angular position, and then another flute and arcuate part of the stem are ground in the manner described above. Thus, the entire peripheral surface of the stem is ground to size by the wheel 19 so that the ground tool marks will run substantially lengthwise of the stem and along the bottom of each flute, which straight-ground tool marks on a punching or perforating tool are desirous and advantageous as explained in my prior Patents Nos. 2,604,742 and 2,622,682.

The tapered, intermediate portion of the element resists breakage that usually occurs, if it does occur, at the junction of the stem with the larger shank. The fingers or tongues 17 further absorb some of the shock on the element created during a perforation operation which further reduces danger of breakage of the punch or element, and hence increases the life of the punch. The engagement of the fingers 17 with the liner sleeve also aids in steadying the punch against breakage stresses in a perforating operation. With this method of grinding, the element, the punch or element can be made directly from a hardened metal blank by simple operations that do not decrease the hardness of the tool.

In the embodiment illustrated in Fig. 11, the perforating element is made as in Figs. 1 to 10, except that the fingers 17 do not engage with the wall of the stripper member, and hence the element is not guided by the stripper member. The fingers 17, however, still perform the function of resisting shock on the tool or element when a perforation of the blank B occurs.

It will be understood that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. A piercing punch for punching a disc from a sheet blank, which comprises a body having at one end a cylindrical punching stem, a larger diameter shank portion at the other end by which said body may be mounted for endwise reciprocation, and an intermediate connecting portion between said stem and said shank portion, said intermediate portion being tapered from the stem to the shank portion, said shank portion having a plurality of tongues at the junction with the tapered portion extending along the tapered portion and along and spaced from the part of the stem adjoining the tapered portion, the outer surfaces of the tongues being continuations of .the peripheral surface of said shank.

2. A piercing punch for punching a disc from a sheet blank, which comprises a body having at one end a cylindrical punching stem, a larger diameter shank portion at the other end by which said body may be mounted for endwise reciprocation, and an intermediate connecting portion between said stem and said shank portion, said intermediate portion being tapered from the stem to the shank portion, said shank portion having a plurality of tongues at the junction with the tapered portion extending along the tapered portion and along and spaced from the part of the stem adjoining the tapered portion,

4 I the outer surfaces of the tongues being continuations of the peripheral surface of said shank, said tongues merging into said tapered portion intermediate the ends of that portion and continuing so merged to the junction of the tapered portion with said shank.

3. A piercing punch for punching a disc from a sheet blank, which comprises a body having at one end a cylindrical punching stem, a larger diameter shank portion at the other end by which said body may be mounted for endwise reciprocation, and an intermediate connecting portion between said stem and said shank portion, said intermediate portion becoming progressively larger in diameter from the stem to the shank portion, said shank portion having a plurality of tongues extending from its junction with the said intermediate portion along that intermediate portion to said stem, the outer surfaces of said tongues being continuations of the peripheral surface of said shank, said tongues being spaced from said stern and the smaller end of said intermediate portion, and merging into said intermediate portion intermediate of the ends of that portion.

4. A piercing punch for punching a disc from a sheet blank, which comprises a body having at one end a cylindrical punching stem, a larger diameter shank portion at the other end by which said body may be mounted for endwise reciprocation, and an intermediate connecting portion between said stem and said shank portion, said intermediate portion becoming progressively larger in diameter from the stem to the shank portion, said shank portion having a plurality of tongues extending from its junction with the said intermediate portion along that intermediate portion to said stem, the outer surfaces of said tongues being continuations of the peripheral surface of said shank, said tongues being spaced from said stem and the smaller end of said intermediate portion, and merging into said intermediate portion intermediate of the ends of that portion, said tongues being arranged at uniform intervals around the shank periphery.

5. A piercing punch for perforating a sheet blank, which comprises a metal body having at one end a relatively small punching stem, a relatively larger diameter shank portion at the other end by which said body may be mounted for endwise reciprocation, and an intermediate portion connecting the stem to said shank, said intermediate portion having flutes extending from its junction with said stern into said shank to decreasing depth and forming a plurality of fingers arranged in spaced relation to one another about said intermediate portion, and at their free ends spaced from said stem but merging gradually into said body as they approach the unfluted part of said body toward the shank.

6. A piercing punch for perforating a sheet blank, which comprises a metal body having at one end a relatively small punching stern, a relatively larger diameter shank portion at the other end by which said body may be mounted for endwise reciprocation, and an intermediate portion connecting the stem to said shank, said intermediate portion having flutes extending from its junction with said stem into said shank to decreasing depths and forming a plurality of fingers arranged in spaced relation to one another about said intermediate portion, and at their free ends spaced from said stem but merging gradually into said body as they approach the unfluted part of said body toward the shank, the surface of said stem and the bottoms of the flutes in said intermediate portion being ground surfaces with the tool marks of such surfaces running lengthwise of the body.

7. A piercing punch for perforating a sheet blank, which comprises a metal body having at one end a relatively small punching stem, a relatively larger diameter shank portion at the other end by which said body may be mounted for endwise reciprocation, and an intermediate portion connecting the stem to said shank, said intermediate portion having flutes extending from its junction with said stem into said shank to decreasing depths and forming a plurality of fingers arranged in spaced relajacent part of said shank being cylindrical and the surface of said stem and the bottoms of the flutes in said intermediate portion being ground surfaces with the tool marks of such surfaces running lengthwise of the body.

References Cited in the file of this patent UNITED STATES PATENTS Fullam Apr. 10, 1860 Aker Oct. 24, 1933 Stimson June 24, 1941 Duncan June 23, 1942 Kopczynski Dec. 23, 1952 

